This invention relates generally to rotational drive assemblies and more particularly concerns a swing drive assembly for load handling devices.
One of the difficulties with large rotational devices such as load handling devices mounted on rotatable beds or turntables is that, due to their size and heavy payloads, high stresses are imposed on the swing drive mechanism and particularly on the teeth of the swing drive gear. If substantially optimum tooth contact and alignment are not maintained during operating cycles the teeth wear rapidly and soon fail when subjected to the high stresses involved.
Accordingly, it is a primary aim of the present invention to provide an improved rotational drive assembly, which may be used to rotate the bed of a load handling device, such as a lift crane and which insures that substantially equalized drive tooth contact is maintained.
A more detailed object is to provide such a rotational drive assembly wherein the main drive shaft is universally journalled so that substantially equalized tooth contact is maintained between the drive gear mounted thereon and each of a pair of laterally disposed pinions which engage a ring gear.
It is also an object to journal the drive shaft in a self-aligning bearing and also to provide a slotted bearing block to limit excess lateral movement of the drive shaft and gear.